Field of the Invention
The present invention relates to a magnetic pole position detecting device for a synchronous motor and a magnetic pole position detecting method for a synchronous motor to determine abnormality in magnetic pole position detection in a synchronous motor.
Description of the Related Art
In order for a synchronous motor to generate a desired torque, current having a phase corresponding to a magnetic pole position needs to be supplied to the synchronous motor. Therefore, to control the synchronous motor, it is necessary to accurately detect the magnetic pole position. The magnetic pole position is detected using a detection signal of a position detector such as an encoder attached to the synchronous motor.
Japanese Laid-Open Patent Publication No. 2009-254045 discloses a magnetic pole position detecting device for a synchronous motor. Briefly describing, the magnetic pole position detecting device calculates a correction amount by implementing PI calculation so that the rotor initial position and the rotor current position coincide with each other, adds this correction amount and the initial value of the magnetic pole position to calculate a magnetic pole position setting value. Then, the magnetic pole position detecting device uses the positional information corresponding to the set magnetic pole position setting value to determine a current vector to be supplied to the synchronous motor. As a result, it is possible to detect the magnetic pole position without performing complicated calculation.